In geophysical terms, the Moon is a planetary-mass object or satellite planet. Its mass is 1.2% that of the Earth, and its diameter is 3,474 km (2,159 mi), roughly one-quarter of Earth's (about as wide as the …

Dec 17, 2025 · The Earth and Moon are tidally locked. Their rotations are so in sync we only see one side of the Moon. Humans didn't see the lunar far side until a Soviet spacecraft flew past in 1959. …

Jan 21, 2026 · Discover fascinating Moon facts—from its size and orbit to gravity, brightness, and temperature. Learn what makes Earth’s Moon truly unique.

• By measuring the ages of lunar rocks, we know that the moon is about 4.6 billion years old, or about the same age as Earth. • The distance between the Earth and its moon averages about...

What is the moon made of, and how did it form? Learn about the moon's violent origins, how its phases shaped the earliest calendars, and how humans first explored Earth's only natural satellite half a …

Sep 7, 2023 · How big is the Moon? The Moon is Earth’s only permanent natural satellite, and it’s the fifth-largest satellite in our solar system. The Moon’s diameter is approximately 2,160 miles (3,475...

3 days ago · NASA is moving into a new phase of space exploration, with major progress across human spaceflight, science missions, and advanced technology. In just one year, the agency has launched …

The Moon Returning humans to lunar missions Why the moon? The Moon is one of Earth's closest habitable neighbors and provides an opportunity to gain valuable experience for missions to Mars …

6 days ago · Moon, Earth’s sole natural satellite and nearest celestial body. Known since prehistoric times, it is the brightest object in the sky after the Sun. Its name in English, like that of Earth, is of …

The moon is the Earth's only natural satellite and the closest celestial object. Learn about the moon and some of the theories about the moon's origin.